Field of the Invention
The present invention relates to a quick coupler.
Background Information
Various types of attachments such as a bucket, a cutter, a breaker, a fork and the like are attached to a work vehicle such as a hydraulic excavator. A quick coupler is known as a component for easily attaching these types of attachments to the work vehicle. The quick coupler is attached to the work vehicle.
For example, the quick coupler described in Japanese Laid-Open Patent Publication No. H7-166571 includes a fixed hook and a moveable hook and these hooks lock with two pins provided on the attachment whereby the attachment is connected to the quick coupler.
When the attachment is attached to the quick coupler with the abovementioned hooks, a lock member is preferably provided to retain the pins in the hooks. For example, the quick coupler described in Japanese Laid-Open Patent Publication No. H7-166571 is made to retain the pins in the hooks by inserting a lock pin in a boss provided on the moveable hook.
However, the lock pin is installed by an operator in the quick coupler described in Japanese Laid-Open Patent Publication No. H7-166571. Because this type of work is complicated, a retaining function is preferably carried out automatically with the lock member when attaching the attachment.
A first arm and a second arm are pivotally attached via a support pin in the quick coupler described in Japanese Laid-open Patent Publication No. 2008-174920. Moreover, a hydraulic cylinder is attached across the first arm and the second arm. Due to the extension of the hydraulic cylinder, a gap between the first arm and the second arm widens whereby an attachment pin is connected to the first arm and the second arm. Moreover, the hydraulic cylinder rotates so as to become horizontal due to the extension of the hydraulic cylinder. Retaining is maintained by a lock member due to the rotation of the hydraulic cylinder and the rotation of the lock member.